阅读说明：本技术 一种具有优异阻隔性能的热塑性淀粉基纳米复合材料及其制备方法 (Thermoplastic starch-based nanocomposite material with excellent barrier property and preparation method thereof ) 是由 邹志明 余劲灵 胡文凯 黎惠敏 李和平 于 2021-09-13 设计创作，主要内容包括：本发明属于高分子复合材料技术领域,涉及一种具有优异阻隔性能的热塑性淀粉基纳米复合材料及其制备方法。本发明复合材料是以热塑性淀粉为基料,以茶多酚、棒状氧化锌纳米粒子为填料。本发明还提供了上述复合材料的制备方法,制备得到的热塑性淀粉基纳米复合材料具有优异的紫外线屏蔽性能、高能短波蓝光阻隔性能、水汽阻隔性能、力学性能、DPPH自由基清除活性(即抗氧化活性)以及低的吸湿性,此外,该复合膜制备工艺简单环保,成本低廉,适于放大生产,在包装、紫外线防护等领域具有很好的应用前景。(The invention belongs to the technical field of polymer composite materials, and relates to a thermoplastic starch-based nano composite material with excellent barrier property and a preparation method thereof. The composite material of the invention takes thermoplastic starch as a base material and takes tea polyphenol and rod-shaped zinc oxide nano particles as fillers. The invention also provides a preparation method of the composite material, and the prepared thermoplastic starch-based nano composite material has excellent ultraviolet shielding performance, high-energy short-wave blue light blocking performance, water vapor blocking performance, mechanical performance, DPPH free radical scavenging activity (namely antioxidant activity) and low hygroscopicity.)

1. A thermoplastic starch-based nanocomposite material with excellent barrier properties is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of plasticizer, 6 parts of tea polyphenol and 1-7 parts of rod-like zinc oxide nanoparticles;

the starch is corn starch;

the plasticizer is glycerol;

the rod-like zinc oxide nanoparticles have a diameter of 50nm and a length of 100-200 nm.

2. The thermoplastic starch-based nanocomposite material with excellent barrier properties according to claim 1, wherein the preparation method of the rod-shaped zinc oxide nanoparticles comprises the following steps:

dissolving zinc acetate dihydrate in 1, 2-propylene glycol, adding deionized water, and stirring and mixing uniformly; adding sodium acetate into the solution, uniformly stirring, heating to 150 ℃, and refluxing for 1 h; then centrifugally separating and drying to obtain rod-like zinc oxide nano particles;

the mass ratio of the deionized water to the zinc acetate dihydrate to the sodium acetate to the 1, 2-propylene glycol is 3.15:5.48:6.15: 86.3.

3. A method for preparing a thermoplastic starch based nanocomposite material with excellent barrier properties according to any of claims 1-2, characterized by comprising the steps of:

(1) adding 100 parts of starch and 30 parts of plasticizer into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 6 parts of tea polyphenol in 800 parts of deionized water, and stirring for 1 hour to obtain a tea polyphenol solution for later use;

(3) dispersing 1-7 parts of rod-shaped zinc oxide nano particles in 800 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(4) and (3) adding the tea polyphenol solution obtained in the step (2) and the rod-shaped zinc oxide nanoparticle dispersion liquid obtained in the step (3) into the starch solution obtained in the step (1), stirring for 1h at 85 ℃ to obtain a uniform film forming liquid, pouring the film forming liquid onto an organic glass dish, and drying for 24h in a vacuum oven at 50 ℃ to obtain the thermoplastic starch-based nanocomposite with excellent barrier property.

Technical Field

The invention belongs to the technical field of polymer composite materials, and particularly relates to a thermoplastic starch-based nano composite material with excellent barrier property and a preparation method thereof.

Background

Biodegradable plastics are made from natural polymers, and are now hot areas of competitive research and development in the world. Among many natural polymer materials, starch has become one of the most potential degradable materials due to its wide source, renewable, edible, low price, and degradable characteristics. In order to make starch plastic like petroleum-based polymers, starch is typically mixed with a plasticizer to convert the starch macromolecules from a crystalline structure to an amorphous state, thereby yielding a thermoplastic starch. However, the thermoplastic starch contains a large amount of hydroxyl, and the mechanical property, the water vapor barrier property, the ultraviolet shielding property, the high-energy short-wave blue light barrier property and the free radical scavenging activity (namely the antioxidant activity) of the biodegradable film material prepared by taking the thermoplastic starch as the raw material cannot meet the higher packaging and using requirements, so that the long-term storage of food and medicines is influenced. Therefore, the thermoplastic starch-based material has important practical significance for widening the application field by improving the mechanical property, the water vapor barrier property, the ultraviolet shielding property, the high-energy short-wave blue light barrier property and the free radical scavenging activity (namely the antioxidant activity) of the thermoplastic starch-based material.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a thermoplastic starch-based nano composite material with excellent barrier property and a preparation method thereof by taking thermoplastic starch as a base material and tea polyphenol and rod-shaped zinc oxide nano particles as fillers.

The technical scheme of the invention is as follows:

a thermoplastic starch-based nanocomposite material with excellent barrier properties is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of plasticizer, 6 parts of tea polyphenol and 1-7 parts of rod-like zinc oxide nanoparticles;

the starch is corn starch; the plasticizer is glycerol;

the rod-like zinc oxide nanoparticles have a diameter of 50nm and a length of 100-200 nm.

The preparation method of the rod-shaped zinc oxide nano particles comprises the following steps:

dissolving zinc acetate dihydrate in 1, 2-propylene glycol, adding deionized water, and stirring and mixing uniformly; adding sodium acetate into the solution, uniformly stirring, heating to 150 ℃, and refluxing for 1 h; then centrifugally separating and drying to obtain rod-like zinc oxide nano particles;

the mass ratio of the deionized water to the zinc acetate dihydrate to the sodium acetate to the 1, 2-propylene glycol is 3.15:5.48:6.15: 86.3.

A method for preparing a thermoplastic starch-based nanocomposite material with excellent barrier properties, comprising the steps of:

(1) adding 100 parts of starch and 30 parts of plasticizer into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 6 parts of tea polyphenol in 800 parts of deionized water, and stirring for 1 hour to obtain a tea polyphenol solution for later use;

(3) dispersing 1-7 parts of rod-shaped zinc oxide nano particles in 800 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(4) and (3) adding the tea polyphenol solution obtained in the step (2) and the rod-shaped zinc oxide nanoparticle dispersion liquid obtained in the step (3) into the starch solution obtained in the step (1), stirring for 1h at 85 ℃ to obtain a uniform film forming liquid, pouring the film forming liquid onto an organic glass dish, and drying for 24h in a vacuum oven at 50 ℃ to obtain the thermoplastic starch-based nanocomposite with excellent barrier property.

Compared with the prior art, the invention has the following beneficial effects:

the thermoplastic starch-based nano composite material prepared by the invention has excellent mechanical property, water vapor barrier property, ultraviolet shielding property, high-energy short-wave blue light barrier property, DPPH free radical scavenging activity (namely antioxidant activity) and low hygroscopicity, and in addition, the composite film has the advantages of simple and environment-friendly preparation process, low cost and suitability for large-scale production.

Detailed Description

In order to better explain the present invention, the present invention is further explained in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

In the following specific examples and comparative example formulations, preparation methods, the starches are all corn starch (CAS number 9005-25-8) available from Aladdin Biotechnology Ltd; the tea polyphenol is an analytical pure grade reagent provided by Luoyang Tianluo biological technology company Limited; the ethanol adopts an analytical pure grade reagent provided by Fuyu fine chemical industry Co.Ltd; zinc acetate dihydrate, anhydrous sodium acetate, and glycerol (glycerin) are analytical pure grade reagents provided by west longa chemical corporation; 1, 2-propylene glycol was used as an analytical grade reagent supplied by the Aladdin Biochemical company.

In the following specific examples and comparative example formulas and preparation methods, the rod-like zinc oxide nanoparticles are self-made nanoparticles (with an average diameter of 50nm and an average length of 100-200 nm), and the preparation method comprises the following steps:

dissolving zinc acetate dihydrate in 1, 2-propylene glycol, adding deionized water, and stirring and mixing uniformly; adding sodium acetate into the solution, uniformly stirring, heating to 150 ℃, and refluxing for 1 h; then centrifugally separating and drying to obtain rod-like zinc oxide nano particles;

the mass ratio of the deionized water to the zinc acetate dihydrate to the sodium acetate to the 1, 2-propylene glycol is 3.15:5.48:6.15: 86.3.

Example 1

A thermoplastic starch-based nanocomposite material with excellent barrier properties is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of glycerol, 6 parts of tea polyphenol and 1 part of rod-shaped zinc oxide nanoparticles.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 6 parts of tea polyphenol in 800 parts of deionized water, and stirring for 1 hour to obtain a tea polyphenol solution for later use;

(3) dispersing 1 part of rod-shaped zinc oxide nano particles in 800 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(4) and (3) adding the tea polyphenol solution obtained in the step (2) and the rod-shaped zinc oxide nanoparticle dispersion liquid obtained in the step (3) into the starch solution obtained in the step (1), stirring for 1h at 85 ℃ to obtain a uniform film forming liquid, pouring the film forming liquid onto an organic glass dish, and drying for 24h in a vacuum oven at 50 ℃ to obtain the thermoplastic starch-based nanocomposite with excellent barrier property.

Example 2

A thermoplastic starch-based nanocomposite material with excellent barrier properties is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of glycerol, 6 parts of tea polyphenol and 3 parts of rod-shaped zinc oxide nanoparticles.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 6 parts of tea polyphenol in 800 parts of deionized water, and stirring for 1 hour to obtain a tea polyphenol solution for later use;

(3) dispersing 3 parts of rod-shaped zinc oxide nano particles in 800 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(4) and (3) adding the tea polyphenol solution obtained in the step (2) and the rod-shaped zinc oxide nanoparticle dispersion liquid obtained in the step (3) into the starch solution obtained in the step (1), stirring for 1h at 85 ℃ to obtain a uniform film forming liquid, pouring the film forming liquid onto an organic glass dish, and drying for 24h in a vacuum oven at 50 ℃ to obtain the thermoplastic starch-based nanocomposite with excellent barrier property.

Example 3

A thermoplastic starch-based nanocomposite material with excellent barrier properties is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of glycerol, 6 parts of tea polyphenol and 5 parts of rod-shaped zinc oxide nanoparticles.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 6 parts of tea polyphenol in 800 parts of deionized water, and stirring for 1 hour to obtain a tea polyphenol solution for later use;

(3) dispersing 5 parts of rod-shaped zinc oxide nano particles in 800 parts of deionized water, and stirring for 1 hour to obtain uniform dispersion liquid for later use;

(4) and (3) adding the tea polyphenol solution obtained in the step (2) and the rod-shaped zinc oxide nanoparticle dispersion liquid obtained in the step (3) into the starch solution obtained in the step (1), stirring for 1h at 85 ℃ to obtain a uniform film forming liquid, pouring the film forming liquid onto an organic glass dish, and drying for 24h in a vacuum oven at 50 ℃ to obtain the thermoplastic starch-based nanocomposite with excellent barrier property.

Example 4

A thermoplastic starch-based nanocomposite material with excellent barrier properties is characterized by comprising the following components in parts by weight: 100 parts of starch, 30 parts of glycerol, 6 parts of tea polyphenol and 7 parts of rod-shaped zinc oxide nanoparticles.

The preparation method comprises the following steps:

(1) adding 100 parts of starch and 30 parts of glycerol into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) dispersing 6 parts of tea polyphenol in 800 parts of deionized water, and stirring for 1 hour to obtain a tea polyphenol solution for later use;

(3) dispersing 7 parts of rod-shaped zinc oxide nano particles in 800 parts of deionized water, and stirring for 1 hour to obtain a uniform dispersion liquid for later use;

(4) and (3) adding the tea polyphenol solution obtained in the step (2) and the rod-shaped zinc oxide nanoparticle dispersion liquid obtained in the step (3) into the starch solution obtained in the step (1), stirring for 1h at 85 ℃ to obtain a uniform film forming liquid, pouring the film forming liquid onto an organic glass dish, and drying for 24h in a vacuum oven at 50 ℃ to obtain the thermoplastic starch-based nanocomposite with excellent barrier property.

Comparative example 1

As a comparative standard for each of the above examples, the present invention provides a thermoplastic starch material prepared without tea polyphenols, rod-like zinc oxide nanoparticles, comprising the steps of:

(1) adding 100 parts of starch and 30 parts of glycerol into 1200 parts of deionized water, stirring for 30 minutes at room temperature, and stirring and dissolving at 85 ℃ to obtain a starch solution for later use;

(2) adding 1600 parts of deionized water into the starch solution obtained in the step (1), and stirring for 1h at 85 ℃ to obtain uniform film forming liquid;

(3) and (3) pouring the film forming liquid in the step (2) onto an organic glass dish, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain the thermoplastic starch material.

And (3) testing structure and performance:

the thermoplastic starch material prepared in the comparative example and the thermoplastic starch-based nanocomposite prepared in the example were subjected to performance tests, wherein the tensile properties were tested according to GB/T1040-2006, the ultraviolet-visible properties were tested using an ultraviolet spectrophotometer (TU-1901, beijing puzzel u ltd) and the average ultraviolet (UVA, UVB and UVC) transmittance was calculated with reference to GB/T18830-2009; the water vapor transmission coefficient was measured according to astm e 96.

The hygroscopicity test method is as follows:

a film sample having dimensions of 20mm by 0.1mm was placed in a vacuum drying oven at 105 ℃ and, after drying for 3 hours, the mass of the film sample (noted as M)₀) (ii) a Then, the dried film sample was placed in a closed container at a relative humidity of 57% and a temperature of 25 ℃ for 48 hours, and the mass (denoted as M) of the film sample was measured₁) (ii) a Moisture absorption (%) of the film sample was 100 ═ M (M)₁-M₀)/M₀。

The DPPH free radical scavenging assay was as follows:

experimental group, 0.2g of film sample was cut into pieces,Soaking in 5mL of ethanol for 24h, and extracting 2mL of supernatant of the soaking solution for later use; then, 1mL of 50mg/L DPPH solution is added into 2mL of the supernatant, and the mixture is shaken up and then placed for standing for 1h under the dark condition at room temperature; the mixture was then tested for absorbance at 517nm (denoted A) using an ultraviolet spectrophotometer (Lambda750, Perkin Elmer instruments Inc.)_sample) (ii) a In a control group, 1mL of 50mg/L DPPH solution is added into 2mL of ethanol, the mixture is shaken up and then placed for standing for 1h under the dark condition at room temperature; the mixture was then tested for absorbance at 517nm (denoted A) using an ultraviolet spectrophotometer (Lambda750, Perkin Elmer instruments Inc.)_control) (ii) a DPPH radical clearance (%) -100 ═ a_control-A_sample)/A_control。

The above performance test data are shown in table 1.

Table 1 composite performance test data

As can be seen from Table 1, the thermoplastic starch-based nanocomposite prepared by the method has excellent ultraviolet shielding performance, high-energy short-wave blue light blocking performance, mechanical property, water vapor blocking performance, DPPH free radical scavenging activity (namely antioxidant activity) and low hygroscopicity, and in addition, the composite film is simple and environment-friendly in preparation process, low in cost, suitable for large-scale production and capable of expanding the application field of the thermoplastic starch-based composite.

The invention is not limited to the examples, and any equivalent changes to the technical solution of the invention by a person skilled in the art after reading the description of the invention are covered by the claims of the invention.